Experimental and Numerical Investigation of Dynamic Impact on Universal Breakaway Steel Post

A closed guardrail system, known as “bullnose” guardrail system, was previously developed to prevent out-of-control vehicles from falling into the elephant trap. The bullnose guardrail system originally used Controlled Release Terminal (CRT) wood posts to aid in the energy absorption of the system. However, the use of CRT had several drawbacks such as grading and the need for regular inspections. Universal Breakaway Steel Post (UBSP) was then developed by the researchers at Midwest Roadside Safety Facility as a surrogate for CRT. In this study, the impact performance of UBSP on the weak-axis and strong-axis was studied through numerical modeling and component testing (bogie testing). A numerical model was developed using an advanced finite element package LS-DYNA to simulate the impact on UBSP. The numerical results were compared to experimental data. Further research on soil models was recommended. The numerical model will be used to investigate other applications for UBSP such as the Midwest Guardrail System (MGS) long span system, guardrail end terminal designs, or crash cushions.